Oil proofing



Patented Nov. 3, 1942 om rRooFmG John H. Holton, Ronald B. Wilson, and Lee E. Kleinmaier, Massillon, Ohio, assignors to Pulp Products Company, Inc., New York, N. Y.,-a cornotation of Delaware No Drawing.

14 Claims.

This invention relates generally to coatings and more particularly to coating compositions which may be applied upon a surface in liquid state to form, upon setting or drying, an oil-resistant film or pellicle.

The invention relates further to a composition which may be applied uponporous and fibrous material to render the same impervious to grease, oil and other like non-aqueous liquids.

In general, the invention comprehends a composition which is adapted for use in treating containers made of fibrous or cellulosic materials such as paper pulp. More specifically, the invention provides an oil-proof moulded pulp container which is admirably suited for dispensing Application December 9, 1938, Serial No. 244,772

- pulp container so treated suitable for shipping motor oils or other similar non-aqueous materials or substances.

For a composition of the type thus generally described to be well suited for commercial use, it should manifest a number of desirable characteristics among which are the following: It should be relatively cheap and economical. It should be capable of manufacture with comparative ease and safety. It should be usable in a form easily applied. After application to a porous surface such as the walls of a. moulded such characteristics that it will not contaminate or otherwise materially interfere with any subpulp container it should quickl set or dry to'- and dispensing lubricating oils and the like.

As a base for the oil-resistant film forming composition, we prefer to use the residual syrupy liquid resulting from the refining of sugar which is known generally as black strap. Or, we may use the non-crystallizable liquid residue from alcohol distillation processes which is known generally as alcohol distillery slop. These residua, sometimes called evaporated molasses residue are non-crystallizable and are relatively very cheap. This accounts generally for our preference for these materials as our basic substancealthough other substantially noncrystallizable sugar-containing syrups may be used. Furthermore, the black strap and alcohol distillery slop contain soluble solids which we believe produce a more desirable coating for a paper pulp container for oils because of the presence of vegetable gums.

According to the invention the non crystallizable sugar syrup is combined with an inert comminuted thickening agent to give body to the composition. In this manner the composition may be adjusted whereby at the temperature at which it is applied a film or pellicle of desirable and uniform thickness may be deposited on the surface being treated. In addition, a'setting agent maybe combined with the syrup which will permit the composition to be sufficiently fluid at the temperature at which it is applied but which will cause the coating to set when stance with which the coated surface is intended to come into contact. The present invention accomplishes the foregoing objectives and desirable results in addition to others hereinafter mentioned.

According to the invention, a composition is provided by utilizing a relatively non-crystallizable sugar syrup to which is added an inert comminuted thickening substance together with a setting agent to cause the film formed by the composition to remain in situ after it is applied to the receiving surface even though subjected to a'wide variety of conditions of temperature and humidity. When compounded according to the invention the composition may be applied to the surface of a fibrous pulp container to produce a stabilized oil-resistant pellicle of sufficient thickness, resiliency and flexibility to render the .cooled to ordinary atmospheric temperatures.

Thus, the oil-resistant pellicle may be maintained in situ on the walls of the container over the range of temperatures to which it is subjected in the customary channels of trade.

We preferably use a high jelly strength hide glue as a setting agent but may use other substances such as, for example, starch, gluten, flour, gelatine and the-like. While a variety of inert comminuted thickening agents or viscosity increasers may be used effectively, we prefer to use comminuted inert material in fiake form for reasons we point out hereinafter. Comminuted mica now available in flake form and also in the so-called exploded form has proved to be very desirable. While either form may be used, we prefer the flake form. comminuted graphite or aluminum may also be used. In general, the comminuted thickener or viscosity increaser should preferably be inert and flat particles are more desirable because they give more tensile strengthv and flexibility to the resultant Broadly, the invention comprehends suitably combining the ingredients in approximate proportions as follows: 100 parts of a non-crystallizable sugar syrup, -30 parts of comminuted inert thickener and 2-10 parts of a setting agent. The syrup may be heated until it is sufiiciently fluid and the comminuted thickener may be combined with it together with the setting agent to form a homogeneous mixture. The composition thus made may be rendered thinner if desired by the addition of water which is compatlble with the mixture since the syrup itself is initially an aqueous solution. I

To illustrate the invention, specific examples of the film-forming composition afforded by the invention for use in coating moulded pulp containers for motor-oil are given:

Example I 100 parts black strap:

'70 parts solids 23 parts water 9 parts glue solution:

3 parts dry glue 6 parts water parts comminuted mica in flake form The glue solution is made by combining dry glue of a high jelly strength with twice its weight of water. The glue is swollen in a part of the water after which the balance of the water may be added and the glue mixture heated toform the glue solution. The glue solution together with the comminuted mica is combined with the black strap and the mixture heated to 90 140 F. and intermixed to form a homogeneous composition which will be relatively thick but fluid at this temperature. A thicker, more viscous or plastic condition results when the composition is cooled to room temperature. The high jelly strength glue will gel or set the composition upon cooling to ordinary handling temperatures yet the composition upon being heated, will again be rendered sufficiently fluid for application to the inner surface of a moulded pulp container.

While it is not essential in producing a suitable oil proof moulded pulp container to apply two coats of the composition to the inner surface, we prefer to do so to increase the factor of safety. In practice in producing one quart size .moulded pulp containers for motor oils, we apply a first coat to the inner surface and after it has set we apply a second coat to the first.

For the first coat we preferably use a thinner solution or composition than that just described. We may make up a separate composition or adjust the composition just described by the addition of water to accord with the following formula:

Example II 100 parts black strap:

'77 parts solids 23 parts water parts glue solution:

10 parts dry glue 20 parts water 25 parts comminuted mica in flake form 145 parts water This produces a thin watery mixture when heated and may be applied to the inner surface of a dry moulded pulp container by flowing the composition heated 90 to 120 F. into the concomposition will form a film which may be dried at room. temperature or the drying may be accelerated in a heated chamber. The purpose of the thinner first coat is to seal the pores of the individual fibres of the pulp wall rather than to fill the voids between the fibres. This coating further serves to reduce the total cost of the oil proofing lining by substantially sealing the pulp surface which materially reduces penetration of the more expensive heavier second coat. However, the first coat may be omitted without'material loss of desirable coating properties and without material loss of oil resistance.

After the first thin coat is applied and dried or set, the second coat may be applied to the first. For the second or inner coating or film, we apply the thick composition according to the formula set forth under Example I.

We have obtained the best results by heating the composition to about 90-140 F. to increase its fluidity. It may be poured into the container having the inner thin dried film. The container may then be tilted to drain out excess liquid after which the film retained on the walls of the container is allowed to dry or set at room temperature. After a short while the container is then ready to be used for filling with motor oil and may then be sealed.

The oil-resistant film thus deposited on the inner surface of the container will be relatively thick, will remain in situ during the process of manufacture and remain so in use. It will not flow away from the walls of the container atv relatively high temperatures or under high relative humidity conditions. Nor will the film or pelliclebecome brittle at relatively low temperatures by reason of the stabilized. moisture content of the film due to the hygroscopic nature of the black strap.

If desired, a further moisture content stabilizing agent may be utilized if the container is to be subjected to extremely low temperatures. We have found that ethylene glycol, glycerine or other similar high boiling point hygroscopic solutions may serve as a moisture content stabilizer.

The following formula has been used with success:

Example III.

Parts Black strap 100 Dry glue 3 Ethylene glycol 6 Comminuted flake mica 25 In addition to the foregoing specific formulae, the following are set forth as further illustrating the invention:

Example IV c Parts Black strap Pearl star 2.5 Comminuted flake mica 1'7 Water 22 tainer and thendraining out the excess. The 7 the other compositions.

Example V Parts Black strap 100 Glue solution 9 'Comminuted graphite in flake form 25 The glue solution may be made by swelling dry glue in a small quantity ofcoldwater and adding 'sufllcient hot water to make the ratio 1 part dry glue to 2 parts water. The composition is made as described above and may be applied to the container in the same manner.

It will be apparent from the foregoing description that an oil proofing coating and a paper container which is light in weight and oil-rerough usage over the wide range of conditions to which they will be subjected in commercial use. Furthermore, such containers are admirably suited for packaging and shipping branded motor oils since they may be sealed at the time of filling. When opened and the motor oil dis- 1 charged they may be easily and conveniently disposed of by the dispenser.

It is to be understood'that the foregoing examples are merely illustrative specific embodiments of the present invention which is of. broad application in the oil proofing field and various modifications, substitutions and changes may be made by those skilled in the art without departing from the spirit and scope thereof and it is further to be understood that the invention is' not limited to the specific embodiments set forth sistant may be produced. Such containers will be cheap to manufacture and will stand up under in situ on the. walls of the container in its customary channels of trade.

5. A composition for forming an oil-resistant film on the walls of a moulded pulp container or the like which comprises 100 parts evaporated molasses residue, 15 to 30 parts inert comminuted graphite to increase the viscosity of said composition and 2 to 10 parts setting agent of the class consisting of glue, gelatin, starch, gluten and flour and adapted to set a film of said composition at ordinary atmospheric temperatures and maintain said film in situ on the walls of the container in its customary channels of trade.

6. A composition for forming an oil-resistant film on the walls of a moulded pulp container or the like which comprises 100 parts evaporated molasses residue selected from the group consisting of black strap and alcohol distillery slop, 15 to 30 parts inert comminuted flow retardin thickener selected from the group consisting of mica, graphite and aluminum, and 2 to 10 parts starch adapted to set a film of said composition at atmospherictemperatures and maintain said him in situ on the walls of the container in its customary channels of trade.

7. A composition for forming an oil-resistant film on the walls of a moulded pulp container which comprises 100 parts evaporated molasses residue, 15 to 30 parts comminuted graphite, and

2 to 10 parts glue of high jelly strength.

8. A composition for forming an oil-resistant film upon the walls of a moulded pulp container or the like which comprises 100 parts of black strap approximately 3 parts .glue with 6 parts water and approximately 25 parts of comminuted mice. in flake form.

and 2 to 10 parts setting agent selected from the class consisting of glue, starch, gelatin, flour and gluten.

2. A composition for forming an oil-resistant film on the walls of a paper pulp container or the like which comprises 100 parts evaporated molasses residue, 15 to 30 parts inert comminuted solid fiow retarding thickener selected from the group consisting of mica, graphite and aluminum, and" 2 to 10 parts glue adapted to set a film of said composition at temperatures below 100 F. and maintain said film in situ on the walls of the container in its customary channels of trade.

3. A composition for forming an oil-resistant film on the walls of a moulded pulp container or the like which comprise 100 parts black strap, 15 to 30 parts inert flake form comminuted flow retarding thickener selected from the group consisting of mica, graphite and aluminum, and 2 to 10 parts glue of high jelly strength to set a film of said composition at temperatures below 9. A composition for forming an oilresistant film upon the walls of a moulded pulp container or the like which comprises parts of black strap, approximately 10 parts glue of high jelly strength, approximately 25 parts comminuted mica and approximately parts water.

10. A composition for forming an oil resistant film upon the walls of a moulded pulp container or the like which comprises 100 parts of black strap, approximately 2.5 parts pearl starch, approximately 17 parts comminuted mica in flake form and approximately 22 parts water.

11. A composition for forming an oil-resistant film upon the walls of a moulded pulp container or the like which comprises 100 parts black strap, approximately 9 parts glue solution consisting of about 3 parts glue and 6 parts water and approximately 25 parts comminuted graphite.

12. A container for dispensing motor oils and the like whichcomprises fibrous walls of paper pulp coated on the interior surface with a pellicle,

formed from a composition comprising 100 parts black strap, an inert comminuted agent selected from the group consisting of mica, graphite and aluminum in sufiicient quantity not exceeding 30 parts to retard the flow of and to give body to the composition and to increase the tensile strength of the pellicle and glue in sufficient quantity not exceeding 10 parts to set the composition at ordinary atmospheric temperature and to maintain the film in situ at temperatures to which the container is subjected in the customary channels of trade.

13. A container for dispensing motor oils and the like which comprises fibrous walls of paper pulp coated on the'interior surface with a pellicle formed Iroma composition comprising 100 parts of a non-crystallizable sugar syrup selected from the class consisting of black strap and alcohol distillery siop, 15 to 30 parts of an inert comminuted solid agent selected from the class con sisting of graphite, mica and aluminum to give body to the composition and to increase the tensile strength of the pellicle formed from the composition and 2 to 10 parts of a setting agent selected from the class consisting of glue, starch, gelatin, flour and gluten to maintain the film in situ at temperatures to which the container is subjected in the customary channels of trade.

14. A container for dispensing motor oils and the like which comprises fibrous walls of paper pulp coated on the interior surface with a film formed from a composition comprising 100 parts black strap, 15 to 30 parts of an inert comminuted mica to give body to the composition and to permit deposition of a film of substantial thickness on said walls and to increase the tensile strength of the deposited film and 2 to 10 parts of a high jelly strength glue to maintain the film in situ under conditions to which the container is subjected in the customary channels of trade.

JOHN H. HOLTON. RONALD B. WILSON. LEE E. EEINMAIER. 

